Industrial storage tanks are widely used to store liquid fuels, chemicals, feed stocks, slurries, aggregates, etc. Such structures can be many stories in height, e.g., 50 feet high, several hundred feet in circumference, and made of steel, metal, or other construction materials of high thickness and tensile strength. The storage tanks can be assembled relatively easily by welding together steel or metal plates in ground-up construction. However, when such storage tanks have outlived their use, they need to be demolished and cut into smaller pieces for transport to landfill, waste, scrap, or recycling facilities. Demolition of such storage tanks is a difficult and dangerous task due to the need to take down a very large, heavy structure of high rigidity and strength.
Currently, a typical tank demotion process requires cutting or punching entry holes in the tank walls at locations around the tank, then laboriously snipping, shearing, cracking, or pulverizing cuts down the tank walls using a hydraulically-operated jaw or shear attachment operated on the end of a hydraulic arm of a heavy carrier or excavator vehicle. As examples, such hydraulically-operated jaws or shears are sold by The Stanley Works, LaBounty Division, of Two Harbors, Minneapolis, under the designation MSD Mobile Shears. However, such hydraulic jaws or shears can cut in bites of only 6 to 12 inches at a time, making it extremely laborious to make long cuts down tank walls many stories in height and repetitively at intervals over hundreds of feet of tank circumference. A typical tank 50 feet in height and 600 feet in circumference could take 30 to 40 hours of work using hydraulic jaws or shears to take it down. In some cases, due to volatile residues of storage material in the tank, the cutting of entry holes in the metal tank walls with flame or electric arc torches cannot be used, making it more difficult to create starter holes.
It would therefore be highly desirable to have improved equipment and a method for demolition of large storage tank structures, particularly those made of steel or metal walls, in a quicker, less labor-intensive manner, and which is mechanically easy to operate and can also readily make starter holes in the tank walls as part of the take-down process.